<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <style>

        /* 列表样式 */
        /* list-style :none|circle|disc|square */
    ul{

        /* list-style: none; */
        list-style: square;
        list-style-image: url("images/icon1.png");
    }
    
    
    </style>
    <title>Document</title>
</head>
<body>
    <ul>
        <li>a</li>
        <li>a</li>
        <li>a</li>
    </ul>
    
</body>
</html>